1. Field of the Invention
The present invention relates generally to a foam generating nozzle. More particularly, the present invention relates to a nozzle for continuously generating foam wherein the nozzle can be employed for the purpose of bathing, cleaning, fire extinguishing, sterilizing or the like by continuously ejecting from the nozzle a spray of a chemical agent liquid mixture and then generating an air filled foam.
2. Description of the Related Art
It has been known that when a chemical agent properly selected for its intended application such as cleaning, fire extinguishing or the like is ejected in the form of foam, cleaning, fire extinguishing or the like can be achieved at a high efficiency with the chemical agent consumed in a small quantity, since the chemical agent remains at a predetermined location or in a predetermined region for a long time.
In view of the above, in recent years, can-shaped containers each having a comparatively small volume while containing chemical agents and high pressure gas or compressed air are practically used as fire extinguishers or as cleaners for a bath tub, a kitchen or other household articles by ejection of the chemical agents in the form of a foam. However, since each of the conventional can-shaped containers contains chemical agents and high pressure gas in only a limited small quantity, their practical application is unavoidably restricted within a narrow range. In other words, they can be used only in a case where chemical agents and high pressure gas, in the form of a foam are required in a small quantity. Another problem is that the so-called flon gas has been usually used in the can-shaped containers of the aforementioned type.
When a large quantity of chemical agents is used in the form of a foam, the chemical agents and high pressure gas are filled at an increased cost. For this reason, it is necessary to develop improved technical means for easily filling each can shaped container with a large quantity of chemical agents and high pressure gas.
An example of a foam generating nozzle serving as means for generating a large amount of chemical foam is the foam type fire extinguisher disclosed Japanese Patent Laid-Open Publication No. 1-259874. According to this prior art, an injector type nozzle tip is disposed in a sleeve for the nozzle so that foam generating liquid is introduced into the fire extinguisher by the action of negative pressure induced by a jet stream of pressurized water to mix the foregoing liquid with the pressurized water. The resultant liquid mixture is ejected through the nozzle tip toward a deflector disposed in front of the nozzle tip so that it collides with the deflector to thereby form a foam serving as a fire extinguishing chemical agent. In addition, a movable sleeve is displaceably received in the nozzle sleeve so as to allow the distance between the foremost end of the movable sleeve and the deflector to be properly adjusted in order to eject or spray the fire extinguishing agent directly toward an item to be extinguished.
The fire extinguisher constructed according to the foregoing prior art is intended to generate a large amount of foam serving as a fire extinguishing agent, using a large quantity of high pressure water. Thus, when this fire extinguisher is employed for an individual dwelling house, use with low pressure tap water causes a number of problems noted below. Specifically, with mixing means having an injector type nozzle tip, a small magnitude of aspirating force is generated by the stream of low pressure water, resulting in a failure in the introduction of the foamable chemical agent into the fire extinguisher. In addition, since the liquid mixture has a comparatively low pressure, only a small quantity of foam is generated when it collides with the plate-shaped deflector. Additionally, due to the fact that the foam generating means, including the deflector, does not include any adjusting means, when pressure of the pressurized water or the kind of chemical agent is changed, the fire extinguisher can not cope with the change, and moreover, can not adjust the physical properties of the foam.
As is apparent from the above description, the conventional fire extinguisher for generating a foam of a chemical agent liquid mixture can not be employed for all of various kinds of applications such as cleaning, fire extinguishing and others. Thus, there arises the need to provide a plurality of foam generating nozzles corresponding to all the foregoing applications.